/*
  Definitions for navigation elements.
*/
// Different elements are styled based on the same set of rules.
$header-height:     3.1875rem !default;      // Height of the header element.
$header-back-color: #f8f8f8 !default;        // Background color for the header element.
$header-hover-back-color: #f0f0f0 !default;  // Background color for the header element (hover).
$header-fore-color:   #444 !default;         // Text color for the header element.
$header-border-color: #ddd !default;         // Border color for the header element.
$nav-back-color:      #f8f8f8 !default;      // Background color for the nav element.
$nav-hover-back-color: #f0f0f0 !default;     // Background color for the nav element (hover).
$nav-fore-color:      #444 !default;         // Text color for the nav element.
$nav-border-color:    #ddd !default;         // Border color for the nav element.
$nav-link-color:      #0277bd !default;      // Color for link in the nav element.
$footer-fore-color:   #444 !default;         // Text color for the footer element.
$footer-back-color:   #f8f8f8 !default;      // Background color for footer nav element.
$footer-border-color: #ddd !default;         // Border color for the footer element.
$footer-link-color:   #0277bd !default;      // Color for link in the footer element.
$drawer-back-color:   #f8f8f8 !default;      // Background color for the drawer component.
$drawer-border-color: #ddd !default;         // Border color for the drawer component.
$drawer-hover-back-color: #f0f0f0 !default;  // Background color for the drawer component's close (hover).
$drawer-close-color:  #444 !default;         // Color of the close element for the drawer component.
$_header-only-bottom-border:  true !default; // [Hidden] Apply styling only to the bottom border of header? (boolean)
$_header-links-uppercase:     true !default; // [Hidden] Should header links and buttons be uppercase? (boolean)
$header-logo-name:    'logo' !default;       // Class name for the header logo element.
$header-logo-font-size: 1.75rem !default;    // Font ize for the header logo element.
$nav-sublink-prefix:   'sublink' !default;   // Prefix for the subcategory tabs in nav.
$nav-sublink-depth:    2 !default;           // Amount of subcategory classes to add.
$_footer-only-top-border:  true !default;    // [Hidden] Apply styling only to the top border of footer? (boolean)
$footer-font-size:    0.875rem !default;     // Font size for text in footer element.
$sticky-name:         'sticky' !default;     // Class name for sticky headers and footers.
$drawer-name:         'drawer' !default;     // Class name for the drawer component.
$drawer-toggle-name: 'drawer-toggle' !default; // Class name for the drawer component's toggle.
$drawer-toggle-font-size: 1.5em !default;    // Font size for the drawer component's toggle. (prefer em units)
$drawer-mobile-breakpoint: 768px !default;   // Mobile breakpoint for the drawer component.
$_drawer-right:     true !default;           // [Hidden] Should the drawer appear on the right side of the screen?
$drawer-persistent-name: 'persistent' !default; // Class name for the persisten variant of the drawer component.
$drawer-width:      320px !default;          // Width of the drawer component.
$drawer-close-name: 'drawer-close' !default; // Class name of the close element for the drawer component.
$drawer-close-size: 2rem !default;           // Size of the close element for the drawer component.
// CSS variable name definitions [exercise caution if modifying these]
$header-fore-color-var:          '--header-fore-color' !default;
$header-back-color-var:          '--header-back-color' !default;
$header-hover-back-color-var:    '--header-hover-back-color' !default;
$header-border-color-var:        '--header-border-color' !default;
$nav-fore-color-var:             '--nav-fore-color' !default;
$nav-back-color-var:             '--nav-back-color' !default;
$nav-hover-back-color-var:       '--nav-hover-back-color' !default;
$nav-border-color-var:           '--nav-border-color' !default;
$nav-link-color-var:             '--nav-link-color' !default;
$footer-fore-color-var:          '--footer-fore-color' !default;
$footer-back-color-var:          '--footer-back-color' !default;
$footer-border-color-var:        '--footer-border-color' !default;
$footer-link-color-var:          '--footer-link-color' !default;
$drawer-back-color-var:          '--drawer-back-color' !default;
$drawer-border-color-var:        '--drawer-border-color' !default;
$drawer-hover-back-color-var:    '--drawer-hover-back-color' !default;
$drawer-close-color-var:         '--drawer-close-color' !default;
// == Uncomment below code if this module is used on its own ==
//
// $universal-margin:        0.5rem !default;      // Universal margin for the most elements
// $universal-padding:       0.5rem !default;      // Universal padding for the most elements
// $universal-border-radius: 0.125rem !default;    // Universal border-radius for most elements
// $universal-box-shadow:    none !default;        // Universal box-shadow for most elements
// $universal-margin-var:          '--universal-margin' !default;
// $universal-padding-var:         '--universal-padding' !default;
// $universal-border-radius-var:   '--universal-border-radius' !default;
// $universal-box-shadow-var:      '--universal-box-shadow' !default;
// :root {
//  #{$universal-margin-var}: $universal-margin;
//  #{$universal-padding-var}: $universal-padding;
//  #{$universal-border-radius-var}: $universal-border-radius;
//  @if $universal-box-shadow != none {
//   #{$universal-box-shadow-var}: $universal-box-shadow;
//  }
// }
//
// ============================================================
/* Navigation module CSS variable definitions */
:root {
  #{$header-back-color-var}: $header-back-color;
  #{$header-hover-back-color-var}: $header-hover-back-color;
  #{$header-fore-color-var}: $header-fore-color;
  #{$header-border-color-var}: $header-border-color;
  #{$nav-back-color-var}: $nav-back-color;
  #{$nav-hover-back-color-var}: $nav-hover-back-color;
  #{$nav-fore-color-var}: $nav-fore-color;
  #{$nav-border-color-var}: $nav-border-color;
  #{$nav-link-color-var}: $nav-link-color;
  #{$footer-fore-color-var}: $footer-fore-color;
  #{$footer-back-color-var}: $footer-back-color;
  #{$footer-border-color-var}: $footer-border-color;
  #{$footer-link-color-var}: $footer-link-color;
  #{$drawer-back-color-var}: $drawer-back-color;
  #{$drawer-hover-back-color-var}: $drawer-hover-back-color;
  #{$drawer-border-color-var}: $drawer-border-color;
  #{$drawer-close-color-var}: $drawer-close-color;
}
// Header styling. - No box-shadow as it causes lots of weird bugs in Chrome. No margin as it shouldn't have any.
header {
  height: $header-height;
  background: var(#{$header-back-color-var}); // Always apply background color to avoid shine through
  color: var(#{$header-fore-color-var});
  @if $_header-only-bottom-border {
    border-bottom: $__1px solid var(#{$header-border-color-var});
  }
  @else {
    border: $__1px solid var(#{$header-border-color-var});
  }
  padding: calc(var(#{$universal-padding-var}) / 4) 0;
  // Responsiveness for smaller displays, scrolls horizontally.
  white-space: nowrap;
  overflow-x: auto;
  overflow-y: hidden;
  // Fix for responsive header, using the grid system's row and column alignment.
  &.#{$grid-row-name} {
    box-sizing: content-box;
    & .#{$header-logo-name} {
      line-height: 1;
    }
  }
  // Header logo styling.
  .#{$header-logo-name} {
    color: var(#{$header-fore-color-var});
    font-size: $header-logo-font-size;
    padding: var(#{$universal-padding-var}) calc(2 * var(#{$universal-padding-var}));
    text-decoration: none;
  }
  // Link and span styling.
  span, button, [type="button"], .#{$button-class-name}, [role="button"] {
    box-sizing: border-box;
    position: relative;
    top: calc(0rem - var(#{$universal-padding-var}) / 4);  // Use universal-padding to offset the padding of the header.
    height: calc(#{$header-height} + var(#{$universal-padding-var}) / 2);  // Fill header.
    background: var(#{$header-back-color-var});        // Apply color regardless to override styling from other things.
    line-height: calc(#{$header-height} - var(#{$universal-padding-var}) * 1.5);
    text-align: center;
    color: var(#{$header-fore-color-var});
    border: 0;
    border-radius: 0;
    margin: 0;
    @if $_header-links-uppercase {
      text-transform: uppercase;
    }
  }
  button, [type="button"], .#{$button-class-name}, [role="button"] {
   &:hover, &:focus {
      background: var(#{$header-hover-back-color-var});
    }
  }
}
// Navigation sidebar styling.
nav {
  background: var(#{$nav-back-color-var});
  color: var(#{$nav-fore-color-var});
  border: $__1px solid var(#{$nav-border-color-var});
  border-radius: var(#{$universal-border-radius-var});
  margin: var(#{$universal-margin-var});
  @if $universal-box-shadow != none {
    box-shadow: var(#{$universal-box-shadow-var});
  }
  * {
    padding: var(#{$universal-padding-var}) calc(1.5 * var(#{$universal-padding-var}));
  }
  a, a:visited {
    display: block;
    color: var(#{$nav-link-color-var});    // Apply regardless to de-stylize visited links.
    border-radius: var(#{$universal-border-radius-var});
    transition: background 0.3s;
    &:hover, &:focus {
      text-decoration: none;
      background: var(#{$nav-hover-back-color-var});
    }
  }
  // Subcategories in navigation.
  @for $i from 1 through $nav-sublink-depth {
    .#{$nav-sublink-prefix}-#{$i} {
      position: relative;
      margin-left: calc(#{$i * 2} * var(#{$universal-padding-var}));
      &:before {
        position: absolute;
        left: calc(var(#{$universal-padding-var}) - #{1 + ($i - 1)*2} * var(#{$universal-padding-var}));
        top: -#{$__1px};
        content: '';
        height: 100%;
        border: $__1px solid var(#{$nav-border-color-var});
        border-left: 0;
      }
    }
  }
}
// Footer styling.
footer {
  background: var(#{$footer-back-color-var}); // Always apply background color to avoid shine through
  color: var(#{$footer-fore-color-var});
  @if $_footer-only-top-border {
    border-top: $__1px solid var(#{$footer-border-color-var});
  }
  @else {
    border: $__1px solid var(#{$footer-border-color-var});
  }
  // margin: $footer-margin;
  padding: calc(2 * var(#{$universal-padding-var})) var(#{$universal-padding-var});
  font-size: $footer-font-size;
  a, a:visited {
    color: var(#{$footer-link-color-var});
  }
}
// Definitions for sticky headers and footers.
header.#{$sticky-name} {
  position: -webkit-sticky; // One of the rare instances where prefixes are necessary.
  position: sticky;
  z-index: 1101;  // Deals with certain problems when combined with cards and tables.
  top: 0;
}
footer.#{$sticky-name} {
  position: -webkit-sticky; // One of the rare instances where prefixes are necessary.
  position: sticky;
  z-index: 1101;  // Deals with certain problems when combined with cards and tables.
  bottom: 0;
}
// Responsive drawer component.
.#{$drawer-toggle-name} {
  &:before {  // No color specified, should use the color of its surroundings!
    display: inline-block;
    position: relative;
    vertical-align: bottom;
    content: '\00a0\2261\00a0'; // Spaces ensure compatibility with buttons that have text and that textless buttons will have some extra padding.
    font-family: sans-serif;
    font-size: $drawer-toggle-font-size;   // Almost hardcoded, should be fully compatible with its surroundings.
  }
  @media screen and (min-width: #{$drawer-mobile-breakpoint}){
    &:not(.#{$drawer-persistent-name}) {
      display: none;
    }
  }
}
[type="checkbox"].#{$drawer-name} {
  height: 1px;
  width: 1px;
  margin: -1px;
  overflow: hidden;
  position: absolute;
  clip: rect(0 0 0 0);
  -webkit-clip-path: inset(100%);
  clip-path: inset(100%);
  + * {
    display: block;
    box-sizing: border-box;
    position: fixed;
    top: 0;
    width: $drawer-width;
    height: 100vh;
    overflow-y: auto;
    background: var(#{$drawer-back-color-var});
    border: $__1px solid var(#{$drawer-border-color-var});
    border-radius: 0; // Set to 0 to override the value from `nav`.
    margin: 0;        // Set to 0 to override the value from `nav`.
    @if $universal-box-shadow != none {
      box-shadow: var(#{$universal-box-shadow-var});
    }
    z-index: 1110;
    @if $_drawer-right {
      right: -$drawer-width;
      transition: right 0.3s;
    }
    @else {
      left: -$drawer-width;
      transition: left 0.3s;
    }
    & .#{$drawer-close-name} {
      position: absolute;
      top: var(#{$universal-margin-var});
      right: var(#{$universal-margin-var});
      z-index: 1111;
      width: $drawer-close-size;
      height: $drawer-close-size;
      border-radius: var(#{$universal-border-radius-var});
      padding: var(#{$universal-padding-var});
      margin: 0; // Fixes the offset from label
      cursor: pointer;
      transition: background 0.3s;
      &:before {    // Transparent background unless hovered over. Does not block text behind it.
        display: block;
        content: '\00D7';
        color: var(#{$drawer-close-color-var});
        position: relative;
        font-family: sans-serif;
        font-size: $drawer-close-size;
        line-height: 1;   // Setting to 1 seems to center the 'X' properly.
        text-align: center;
      }
      &:hover, &:focus {
        background: var(#{$drawer-hover-back-color-var});
      }
    }
    @media screen and (max-width: #{$drawer-width}) {
      width: 100%;
    }
  }
  &:checked + * {
    @if $_drawer-right {
      right: 0;
    }
    @else {
      left: 0;
    }
  }
  @media screen and (min-width: #{$drawer-mobile-breakpoint}){
    &:not(.#{$drawer-persistent-name}) + * {
      position: static;
      height: 100%;
      z-index: 1100;
      & .#{$drawer-close-name} {
        display: none;
      }
    }
  }
}
